The present invention relates to a display device in which an IC (Integrated Circuit) or the like is mounted by a method such as chip on glass (hereinafter referred to as COG). An IC is electrically connected to a glass substrate by aligning a solder bump formed on the IC to a terminal pad formed on the substrate, bringing them into contact with each other, and thereafter heating and melting the solder bump. Alternatively, the connection is made by what is called a wire bonding method, in which a terminal protruding from an IC and a terminal on the substrate are connected by a wire. Further, the present invention relates to a sealing structure of a display device in which an IC is mounted by using these methods.